As represented by the WWW (World Wide Web), the users of the internet are drastically increasing in recent years. By using the internet, data can be exchanged between arbitrary computers connected with the internet, or an access can be made to a service provided by a computer so that the function of the service can be utilized. In the WWW, for example, the user is enabled by inputting an address called the URL (uniform Resource Locator) to the browser to peruse the data which are laid open by the various computers connected with the internet designated by the URL. By making an access to not the WWW but a mail server, on the other hand, electronic mails can be transmitted and received, or the services such as the FTP for exchanging files with another computer can be utilized.
These applications such as the WWW belong to a system of the server-client type, the roles of which are shared between a server providing the service and a client utilizing the service. In the internet, however, an application of another type acts. In a teleconference system which is realized in the T.120 recommendation standardized in the ITU-T, not only data can be exchanged between specific servers, as viewed at least from the user, but also files can be transmitted or still images can be shared between a plurality of computers having participated in the conference.
In order to utilize these applications, the user is required to ask input or set the address of a partner terminal by any means. In the case of the WWW, it is necessary to input the URL to the browser. In order to utilize the electronic mail, it is necessary to set the address of the mail server for the electronic mail application. Since the address or the like of the mail server is hardly changed, it is usually set by inquiring that of the manager or the like of the mail server.
The utilization of the network such as the internet is flourishing on one hand, and the device technique or the like is developing on the other hand so far as to realize an information device which is so compact that it can be easily carried about. In accordance with a development of the radio technique, on the other hand, there has been widely used the mobile communication system, as represented by a mobile telephone, or a wireless LAN. Under these circumstances, there has been flourishing the ad hoc network technique for generating a network environment by gathering the information devices without any preceding setting.
In the ad hock network, too, it is desired that various applications can be utilized as in the network of the prior art. In the ad hoc network, however, there will occur a situation in which it is impossible to know in advance what terminal is present. Since the address of the computer may be different each time, on the other hand, it is difficult to ask someone for the address in advance.
In the operating system of Microsoft, for example, as described in Getting Started Microsoft Windows 98 (of the registered trade mark), a list of devices, which are connected through the network and properly set, can be viewed by the user of the network computer so that a connectable device can be known even in the ad hoc network. However, what can be done by the computer as can be deemed as the network computer, is to make an access to its local file system but not to execute other applications.
By using the function of the network computer of the operating system of Microsoft, the user is enabled to know which computer exists in the periphery and whether or not it can communicate. When an application is to be actually executed, however, there is a problem that not only the addresses of computers having gathered ad hoc but also what functions can be done by the computers is unknown.
In the following, the functions to be provided by the computer for other communication devices, as can be executed by the teleconference application operated by the FTP server or the mail server, that is, the functions to be executed for communications will be generally called the “services”. Since it cannot be practically expected that all the computers have an identical construction, it is difficult to know the services to be provided by other computers in advance.
Even when there are a number of communicable computers existing around, on the other hand, there is another problem that it is difficult to select a desired one of the listed computers.
Therefore, the invention has an object to provide means for enabling the user to designate a proper communication partner easily in a network environment generated ad hoc.